Method of manufacturing wire and porcelain elements



June 3, 1930; F. s. M CULLOUGH 1,761,577

METHOD OF MANUFACTURING WIRE AND PORCELAIN ELEMENTS Filed Jan. 5, 1926 Patented June 3, 1930 PATENT, OFFICE A rnnnnnrox ,s. mcoULLouon, or nnenwoon, PENNSYLVANIA METHOD OF MANUFACTURING W'IRE AN D PORCELAIN ELEMENTS Application filed January 5,, was Serial No. 79,351.

' This invention relates to a method of placing wires imporcelain or other refractory or ceramic material.

In certain types of electrical apparatus, it is customary to have a wire embedded in a refractory insulating material. Reference is made particularly toelectric heaters of certaintypes, such as those used in confined spaces, as for instance, the heaters 12 of cathodes'i-ofcertaintypes of space discharge devices. 1

In heatrs of this type, the best results are effected-if the wire is in intimate contact with the refractory material. At the 1:: same time, the heater must be manufactured according to a process that will not destroy the frail and readily oxidizable heater wire.

lengths after it has set, insert the heater .wires, and then fire the porcelain, contracting it onto the wires, the firing taking place under. conditions conducive to a maximum shrinkage, and without liability of oxidation ofthe heater wire.

The nature of the invention may be readily understood by reference to the accompanying drawings, wherein Figure 1 r resents an elevation of a section of unfire porcelain before the passage showing the material somewhat'leirger than that commonly'employed;

Figure 2-is a longitudinal section through the porcelain rod of Figure 1 with the heater 4 wire in place; and

Figure?) is a vertical section illustrating diagrammatically a manner of firing the as sembled structure shown in Figure 2.

In the drawings, 2 represents a length of 5 rod 'of porcelain or other refractory mate- ,-porcelain, the holes 3 and of the heater wire therethrough, the figure" rial haying parallel holes 3 and 4 extending longitudinally therethrough. This section of rod is cut from a length of such mate- .rial formed by a process of extrusion after the porcelain has set and before it is fired. A bowed or hairpin shaped wire 5 of suitable resistance is then passed through the holes 3 and 4, as shown in Figure 2. This wire may be of tungstenor other suitable material.

The heater element, as the porcelain with a the wire passed therethrough may be termed, may then be enclosed in a suitable chamber and fired. In Figure 3 I have illustrated one manner of doing this wherein the heater element is suspended within a. silica or other refractory chamber 6 having an outlet connection 7 leading to a suitable vacuum pump, not shown. I haveshown chamber 6 as being closed by a suitable plug 8. p

* After the chamber 6 has been evacuated, and while the vacuum is maintained therein, it is placed in a suitable heating furnace, designated 9 and the porcelain 2 is fired at a high temperature. The refractorymaterial contracts onto the metal, so that the two are in more intimate contact than has heretofore been possible. At thesame time, the temperature can be sufiiciently high to effect a thorough burning of the refractory material without damage to the heating wii'e, as oxidation does not occur.

After being heated at thedesired temperature for a. necessary period of time, the chamber may be removed from the furnace.

Heaters as thus produced are highly satisfactory. Assembly thereof is facilitated be cause when the wires are put. through the 4 are fairly open. may be made in Various detail changes the practice of the invention, and the invention is not restricted to the manufacture of the particularconstruction of heatershown,

or to the useof any particular apparatus.

I claim as my invention: A 1.; A method of making refractory bodies with wires therethrough which consists in forming a length of refractory rod with a hole therethrough, allowing the refractor material to set, then passing a wire througii tory into intimate contact with the wire and which consists in formin material having a hole t erethrough, passthe hole, and firing the refractory rod with the wire therein under conditions which preclude oxidation of the wire.

2. A method of making refractory bodies with wires therethrough which consists in forming a length of unvitrified refractory rod with a hole therethrough, allowing the refractory material to set, then passing a wire through the hole in the unvitrified rod,

and firing the refractory rod with the wire therein in a vacuum.

3. A method of making heater elements ing a wire through the hole, enclosing the assembled structure in a chamber, and heating the chamber to fire the ceramic material while maintaining a vacuum in the chamber.

4. A method of forming heaters which consists in forming a rod of unvitrified porcelain with a hole therethrough, allow-- to remove the gas therefrom and prevent oxidation of the wire.

In testimony whereof I have hereunto set my hand.

FREDERICK S. MCCULLOUGH.

CERTIFICATE or CORRECTION.

Patent No. l, 761, 577.

FREDERICK/S. McCULLOUGH.

a rod of ceramic Granted June 3; 1930, to

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Page 1, line 98, claim 1, before the word "refractory" insert the word unvitrified, and page 2, line 1, same claim, after the word "hole" insert the words in the unvitrified rod; same page, line 6, claim 2, strike out "unvitrified", and line 9, strike out "in the unvitrified rod"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

' Signed and sealed this 13th day of January, A. D. 1931.

(Seal) M. J. Moore, Acting Commissioner of Patents. 

